Gas turbine engines operate to produce mechanical work or thrust. Specifically, land-based gas turbine engines typically have a generator coupled thereto for the purposes of generating electricity. A gas turbine engine comprises an inlet that directs air to a compressor section, which has stages of rotating compressor blades. As the air passes through the compressor, the pressure of the air increases. The compressed air is then directed into one or more combustors where fuel is injected into the compressed air and the mixture is ignited. The hot combustion gases are then directed from the combustion section to a turbine section by a transition duct. The hot combustion gases cause the stages of the turbine to rotate, which in turn, causes the compressor to rotate.
The hot combustion gases are directed through a turbine section by turbine blades and vanes. Stationary turbine vanes precede each stage of rotating blades in order to direct the flow of hot combustion gases onto the blades at the appropriate angle to maximize turbine efficiency. These blades and vanes are subject to extremely high operating temperatures, stresses, and strains. Typical areas of high stress and strain for a blade and vane include the platform area as well as the joint between the airfoil and the platform. To help reduce the operating temperatures of the turbine blades and vanes, a cooling fluid such as air is often passed through the blade or vane and exits through the blade tip or through holes in the airfoil surface. However, cooling alone is not always sufficient or possible depending on the geometry of the blade or vane and the operating conditions of the engine.